It has not yet been officially confirmed who Chastain will be playing in X-Men: Dark Phoenix, but if the early reports of her casting are true, she will reportedly be playing Princess-Majestrix Lilandra Neramani in the film, who is the empress of the Shi’ar alien empire in the comics. It has been previously reported that Neramani will be on a mission to imprison (and destroy) Jean as the ultra-powerful Dark Phoenix, throughout the course of the film.
James McAvoy (Professor Xavier), Michael Fassbender (Magneto), Jennifer Lawrence (Mystique), Nicholas Hoult (Beast), Tye Sheridan (Cyclops), Evan Peters (Quicksilver), Kodi-Smit McPhee (Nightcrawler), Alexandra Shipp (Storm) and Sophie Turner (Jean Grey) are all returning for the film.

X-Men: Dark Phoenix will release in November 2, 2018.
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